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Metformin and mtor

Maike Zimmermann, Aruni P S Arachchige-Don, Michaela S Donaldson, Tommaso Patriarchi, Mary C Horne
Definition of cell cycle control proteins that modify tumor cell resistance to estrogen (E2) signaling antagonists could inform clinical choice for estrogen receptor positive (ER+) breast cancer (BC) therapy. Cyclin G2 (CycG2) is upregulated during cell cycle arrest responses to cellular stresses and growth inhibitory signals and its gene, CCNG2, is directly repressed by E2-bound ER complexes. Our previous studies showed that blockade of HER2, PI3K and mTOR signaling upregulates CycG2 expression in HER2+ BC cells, and that CycG2 overexpression induces cell cycle arrest...
October 18, 2016: Cell Cycle
Mohamed Alalem, Alpana Ray, Bimal K Ray
Activation of mTOR is implicated in the development and progression of breast cancer. mTOR inhibition exhibited promising antitumor effects in breast cancer; however, its effect is compromised by several feedback mechanisms. One of such mechanisms is the upregulation of mTOR pathway in breast cancer cells. Despite the established role of mTOR activation in breast cancer, the status of total mTOR protein and its impact on the tumor behavior and response to treatment are poorly understood. Besides, the mechanisms underlying mTOR protein degradation in normal and cancer breast cells are still largely unknown...
October 17, 2016: Cancer Medicine
Pamela T Soliman, Qian Zhang, Russell R Broaddus, Shannon N Westin, David Iglesias, Mark F Munsell, Rosemarie Schmandt, Melinda Yates, Lois Ramondetta, Karen H Lu
OBJECTIVE: Metformin reduces cancer incidence and improves overall survival in diabetic patients. In preclinical studies, metformin decreases endometrial cancer (EC) cell growth by activation of AMPK/mTOR inhibition. We sought to determine the effects of metformin on serum/tumor biomarkers in women with EC. METHODS: In this prospective trial, newly diagnosed EC patients underwent pre-treatment blood draw/endometrial biopsy, were administered oral metformin 850mg daily for ≥7days, and underwent post-treatment blood draw/definitive surgery...
October 13, 2016: Gynecologic Oncology
Gabriela Figueroa-González, Verónica García-Castillo, Jossimar Coronel-Hernández, Eduardo López-Urrutia, Sonia León-Cabrera, Luis E Arias-Romero, L I Terrazas, Miriam Rodríguez-Sosa, Alma Delia Campos-Parra, Eduardo Zúñiga-Calzada, Cesar Lopez-Camarillo, Fermín Morales-González, Nadia J Jacobo-Herrera, Carlos Pérez-Plasencia
Colorectal cancer (CRC) is an important health issue worldwide, accounting for the third place of cancer incidence. Chronic inflammation, as seen in Crohn's disease and ulcerative colitis, is the most important risk factor for developing CRC, as it favours neoplastic transformation by enhancing epithelial cell turnover in the colonic mucosa. Treatments for CRC need to be improved; currently they are not specific and have several secondary effects in patients. The main objective of this work was to evaluate a new therapeutic strategy against a colitis-related colorectal cancer in vivo and in vitro by targeting mTOR-signaling and lactate dehydrogenase A...
2016: Journal of Cancer
Sreenithya Ravindran, Vinitha Kuruvilla, Kerry Wilbur, Shankar Munusamy
Metformin, a well-known anti-diabetic agent, is very effective in lowering blood glucose in patients with type 2 diabetes with minimal side-effects. Metformin is also being recommended in the treatment of obesity and polycystic ovary syndrome. Metformin elicits its therapeutic effects mainly via activation of AMP-activated kinase (AMPK) pathway. Renal cells under hyperglycemic or proteinuric conditions exhibit inactivation of cell defense mechanisms such as AMPK and autophagy, and activation of pathologic pathways such as mammalian target of rapamycin (mTOR), endoplasmic reticulum (ER) stress, epithelial-to-mesenchymal transition (EMT), oxidative stress, and hypoxia...
September 14, 2016: Journal of Cellular Physiology
Lu Liu, Yilin Pan, Yang Song, Xiaofan Su, Rui Ke, Lan Yang, Li Gao, Manxiang Li
The aims of the present study were to examine the effect of adenosine monophosphate-activated protein kinase (AMPK) activation on airway smooth muscle cells (ASMCs) proliferation and to address its potential mechanisms. Platelet derived growth factor (PDGF) activated phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway, and this in turn up-regulated S-phase kinase-associated protein 2 (Skp2) and consequently reduced cyclin dependent kinase inhibitor 1B (p27) leading to ASMCs proliferation...
September 4, 2016: European Journal of Pharmacology
Heloíza Paranzini Bordini, Jean Lucas Kremer, Tatiane Renata Fagundes, Gabriella Pasqual Melo, Ivete Conchon Costa, Suelen Santos Da Silva, Alessandra Lourenço Cecchini, Carolina Panis, Rodrigo Cabral Luiz
Colorectal Cancer (CRC) is the third most frequent type of cancer worldwide. In the past few years, studies have revealed a protective effect of metformin (MET - an anti-hyperglycemic drug, used to treat type 2 diabetes), against CRC. The protective effect of MET has been associated with AMPK activation (and mTOR inhibition), resulting in suppressed protein synthesis, and reduced cell proliferation in malignant transformed cells. To elucidate new mechanisms for the protective effect of metformin, we evaluated the oxidative stress and inflammatory process modulation, since these processes are strictly involved in colorectal carcinogenesis...
September 1, 2016: Molecular Carcinogenesis
Chuan Shen, Chenghong Peng, Baiyong Shen, Zhecheng Zhu, Ning Xu, Tao Li, Junjie Xie
Immunosuppressive agents used postoperatively after liver transplantation (LT) for hepatocellular carcinoma (HCC) favor recurrence and metastasis. Therefore, new effective immunosuppressants are needed. This retrospective study assessed combined sirolimus and metformin on survival of HCC patients after LT. In 2001-2013, 133 HCC patients with LT were divided into four groups: sirolimus and metformin combination (Sir+Met), sirolimus monotherapy (Sir), other immunosuppressants in diabetes mellitus (DM) patients without metformin (No Sir with DM), and other immunosuppressants in patients without DM (No Sir without DM)...
August 25, 2016: Oncotarget
Ichiro Kawashima, Keita Kirito
Metformin suppresses the growth of a variety of malignant hematologic cells. It is widely accepted that metformin inhibits the growth of malignant cells primarily by suppressing the mTOR pathway or regulating autophagy. In contrast, we found another possible mechanism that inhibits the growth of malignant cells, suppression of the activity of the oncogenic kinase JAK2V617F. We identified at least two distinct mechanisms involved in metformin-induced JAK2V617F inhibition. First, metformin increases reactive oxygen species levels in these cells, leading to the inhibition of SHP-2, a positive regulator of JAK2V617F...
August 27, 2016: Experimental Hematology
Adan Rios, Sigmund H Hsu, Angel Blanco, Jamie Buryanek, Arthur L Day, Mary F McGuire, Robert E Brown
UNLABELLED: Glioblastoma multiforme (GBM) is a CNS (central nervous system) malignancy with a low cure rate. Median time to progression after standard treatment is 7 months and median overall survival is 15 months [1]. Post-treatment vasculogenesis promoted by recruitment of bone marrow derived cells (BMDCs, CD11b+ myelomonocytes) is one of main mechanisms of GBM resistance to initial chemoradiotherapy treatment [2]. Local secretion of SDF-1, cognate ligand of BMDCs CXCR4 receptors attracts BMDCs to the post-radiation tumor site...
2016: Oncoscience
Nicole M A White-Al Habeeb, Julia Garcia, Neil Fleshner, Bharati Bapat
BACKGROUND: This study explored the biological effects of metformin on prostate cancer (PCa) cells and determined molecular pathways and epigenetic regulators implicated in its mechanism of action. METHODS: We performed mRNA expression profiling in 22Rv1 cells following 2.5 mM and 5 mM metformin treatment. Genes significantly modified by metformin treatment were ranked based on altered expression, involvement with cancer-related processes, and reported dysregulation in PCa...
July 12, 2016: Prostate
Joshua Kilgore, Amanda L Jackson, Leslie H Clark, Hui Guo, Lu Zhang, Hannah M Jones, Timothy P Gilliam, Paola A Gehrig, Chunxiao Zhou, Victoria L Bae-Jump
OBJECTIVE: Biguanides are anti-diabetic drugs that are thought to have anti-tumorigenic effects. Most pre-clinical studies have focused on metformin for cancer treatment and prevention; however, buformin may be potentially more potent than metformin. Given this, our goal was to evaluate the effects of buformin on cell growth, adhesion and invasion in endometrial cancer cell lines. METHODS: The ECC-1 and Ishikawa endometrial cancer cell lines were used. Cell proliferation was assessed by MTT assay...
2016: American Journal of Translational Research
Giada Poli, Giulia Cantini, Roberta Armignacco, Rossella Fucci, Raffaella Santi, Letizia Canu, Gabriella Nesi, Massimo Mannelli, Michaela Luconi
Adrenocortical carcinoma (ACC) is a rare heterogeneous malignancy with poor prognosis. Since radical surgery is the only available treatment, more specific and effective drugs are urgently required. The anti-diabetic drug metformin has been associated with a decreased cancer prevalence and mortality in several solid tumors, prompting its possible use for ACC treatment.This paper evaluates the in vitro and in vivo anti-cancer effects of metformin using the ACC cell model H295R.Metformin treatment significantly reduces cell viability and proliferation in a dose- and time-dependent manner and associates with a significant inhibition of ERK1/2 and mTOR phosphorylation/activation, as well as with stimulation of AMPK activity...
July 6, 2016: Oncotarget
Angiolo Gadducci, Nicoletta Biglia, Roberta Tana, Stefania Cosio, Martina Gallo
Metformin exerts antitumor effects mainly through AMP-activated protein kinase [AMPK] activation and phosphatidylinositol 3-kinase [PI3K]-Akt-mammalian target of rapamycin [mTOR] inhibition. This drug leads to activation of the cellular energy-sensing liver kinase B1 [LKB1]/AMPK pathway. LKB1 is implicated as a tumor suppressor gene in molecular pathogenesis of different malignancies. AMPK is a serine/threonine protein kinase that acts as an ultra-sensitive cellular energy sensor maintaining the energy balance within the cell...
September 2016: Critical Reviews in Oncology/hematology
Yan-Ling Wu, Yu-Jing Zhang, You-Li Yao, Zhi-Man Li, Xin Han, Li-Hua Lian, Yu-Qing Zhao, Ji-Xing Nan
The study evaluated the potential protective effect and underlying mechanism of Cucurbitacin E (CuE) in both thioacetamide-induced hepatic fibrosis and activated HSCs. CuE inhibited the proliferation of activated HSC/T-6 cells in a concentration- and time-dependent manner; triggered the activation of caspase-3, cleaved PARP, altered ratio of bcl-2-to-bax, and affected cytochrome C protein in a time- and concentration-dependent manner. CuE arrested activated HSCs at the G2/M phase. Furthermore, CuE reduced levels of p-Erk/MAPK and also inhibited the protein and mRNA expressions of α-SMA, TIMP-1 and collagen I in activated HSC-T6 cells...
September 6, 2016: Toxicology Letters
Stanisław Sośnicki, Małgorzata Kapral, Ludmiła Węglarz
Epidemiological studies have shown that metformin, a first line therapeutic agent for diabetes mellitus, reduced the risk of developing various malignancies. Several preclinical studies established some possible mechanisms of its anticancer effects. The primary effect of metformin action is a decrease in cell energy status, which activates AMP-activated kinase (AMPK), a cellular metabolic sensor. This event is followed by a decrease in serum concentrations of insulin and insulin growth factor I (IGF-I), the potent mitogens for cancer cells...
October 2016: Pharmacological Reports: PR
Juliana Velez, Rongqing Pan, Jason T C Lee, Leonardo Enciso, Marta Suarez, Jorge Eduardo Duque, Daniel Jaramillo, Catalina Lopez, Ludis Morales, William Bornmann, Marina Konopleva, Gerald Krystal, Michael Andreeff, Ismael Samudio
Metformin displays antileukemic effects partly due to activation of AMPK and subsequent inhibition of mTOR signaling. Nevertheless, Metformin also inhibits mitochondrial electron transport at complex I in an AMPK-independent manner, Here we report that Metformin and rotenone inhibit mitochondrial electron transport and increase triglyceride levels in leukemia cell lines, suggesting impairment of fatty acid oxidation (FAO). We also report that, like other FAO inhibitors, both agents and the related biguanide, Phenformin, increase sensitivity to apoptosis induction by the bcl-2 inhibitor ABT-737 supporting the notion that electron transport antagonizes activation of the intrinsic apoptosis pathway in leukemia cells...
June 6, 2016: Oncotarget
Yi Zhao, Wei Wang, Shutao Guo, Yuhua Wang, Lei Miao, Yang Xiong, Leaf Huang
Metformin, a widely implemented anti-diabetic drug, exhibits potent anticancer efficacies. Herein a polymeric construction of Metformin, PolyMetformin (PolyMet) is successfully synthesized through conjugation of linear polyethylenimine (PEI) with dicyandiamide. The delocalization of cationic charges in the biguanide groups of PolyMet reduces the toxicity of PEI both in vitro and in vivo. Furthermore, the polycationic properties of PolyMet permits capture of siRNA into a core-membrane structured lipid-polycation-hyaluronic acid (LPH) nanoparticle for systemic gene delivery...
2016: Nature Communications
Seiji Ueno, Toru Kimura, Takashi Yamaga, Akihiko Kawada, Toshiaki Ochiai, Hitoshi Endou, Hiroyuki Sakurai
BACKGROUND: In many cancer cells, L-type amino acid transporter 1 (LAT1) transports neutral amino acids with bulky side chain, which activate mammalian target of rapamycin (mTOR) to cause cell proliferation. An anti-diabetic drug, metformin, has been shown to activate AMP-activated protein kinase (AMPK), which leads to inhibition of mTOR. LAT1 inhibition in combination with metformin could result in more prominent suppression of mTOR activity. PURPOSE: Anti-proliferative effect of a newly developed LAT1 specific inhibitor JPH203 in combination with metformin is evaluated in 2 head and neck cancer cell lines, Ca9-22 and HEp-2 cells and in nude mice inoculated with Ca9-22 cells...
June 2016: Journal of Pharmacological Sciences
Elisabet Cuyàs, Salvador Fernández-Arroyo, Tomás Alarcón, Ruth Lupu, Jorge Joven, Javier A Menendez
We hypothesized that women inheriting one germline mutation of the BRCA1 gene ("one-hit") undergo cell-type-specific metabolic reprogramming that supports the high biosynthetic requirements of breast epithelial cells to progress to a fully malignant phenotype. Targeted metabolomic analysis was performed in isogenic pairs of nontumorigenic human breast epithelial cells in which the knock-in of 185delAG mutation in a single BRCA1 allele leads to genomic instability. Mutant BRCA1 one-hit epithelial cells displayed constitutively enhanced activation of biosynthetic nodes within mitochondria...
May 31, 2016: Oncotarget
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